1. Field of the Invention
The present invention relates to a gear assembly for a disk transport apparatus, and more particularly, to a gear assembly for driving a tray of a minidisk (which is a kind of draw type data memory device) in a disk player.
2. Prior Arts
Recently, in computers or audios or image devices, a number of pits are formed on a surface of a disk to record data. A laser beam is projected onto the disk surface with rotating the disk at a high speed in a disk player and light reflected from the disk is optically read out and converted into an electric signal for reproduction of an image and/or sound or other data. In such a disk player, a disk is mounted on a disk tray and then the disk tray is moved so that the disk is located under the head of a disk driving apparatus. An example of such a transporting device for disk is disclosed in U.S. Pat. No. 4,839,881 (issued to Takahara et al.).
The disk tray is supported by cylindrical bearings provided therebelow so that the disk tray may move smoothly along a guide rail. On the side surfaces of the disk tray, a rack having a number of slots formed thereon is provided for transporting the dynamic force to the disk tray so that the disk tray may be moved along the longitudinal direction thereof. The disk tray is operated reciprocatingly in a predetermined distance.
In a general disk driving system, a motor is operated for applying the dynamic force, to the disk tray having a rack on a side thereof so that the disk tray may move reciprocatingly. More particularly, the rotation force of the motor is firstly applied to a moving rack (which is often referred to as an "operation control member") which can be moved reciprocatingly in a short distance so that the moving rack is moved by a predetermined distance. A plurality of gears are engaged between the moving rack and the disk tray rack so that the dynamic force of the motor is transferred to the disk tray.
The gears are constructed in such a manner that the disk tray may be moved by a longer distance corresponding to the short distance of the moving rack. In such a case, in order to amplifyingly transfer the moving distance of the moving rack to the disk tray, a pair of gears (which is often referred to as a "double gear") are used to adjust the relationship of the reciprocating distances of the moving rack and the disk tray. One example of such a double gear is disclosed in U.S. Pat. No. 4,442,516 (issued to Tadashi Funabshi). FIG. 1 is an exploded view of the double gear as described in the above U.S. Patent.
The double gear as shown in FIG. 1, is mounted on a guide rail (not shown) so that a first gear 26 engaged with the rack of the disk tray and a second gear 25 may rotate coaxially and the double gear is supported by a support pin (not shown). First gear 26 has an axial through a hole 31 in the center thereof and confronting arc-shaped engagement holes 32 are formed at diametrically opposite positions. Second gear 25 has an axial through hole 30 in the center thereof and a pair of confronting pins 27 are rigidly fixed on the upper surface.
The diameter ratio (D1:D2) of first gear 25 to second gear 26 is about 2:1, that is, the ratio of numbers of gear teeth is about 2:1.
A moving rack (not shown) is reciprocatingly moved by a rotational force of a motor. The reciprocating movement is transferred to second gear 25 engaged with the moving rack to rotate second gear 25. The rotation of second gear 25 is transferred to first gear 26 by two pins 27 and two engagement holes 32. First gear 26 drives another gear or a disk tray rack engaged with first gear 26 to reciprocatingly move the disk tray. In this way, a disk is transported under a disk driver head or is removed therefrom.
When using a conventional double gear as described above, pins 27 of second gear 25 strike the sidewalls of engagement holes 32 of first gear 26 during the reciprocating movement of the disk tray. Therefore, pins 27 are easily broken due to the impact occurred in the reciprocating movement so that the double gear must be replaced with a new one occasionally. Also, since the rotating force of second gear 25 is directly transferred to first gear 26, an overload is unpreferably applied to the driving motor.